Vision is superior to touch in shape perception even with equivalent peripheral input

Results from previous studies suggest that two-dimensional spatial patterns are processed similarly in vision and touch when the patterns are equated for effective size or when visual stimuli are blurred to mimic the spatial filtering of the skin. In the present study, we measured subjects' ability to perceive the shape of familiar and unfamiliar visual and tactile patterns to compare form processing in the two modalities. As had been previously done, the two-dimensional tactile and visual patterns were adjusted in size to stimulate an equivalent number of receptors in the two modalities. We also distorted the visual patterns, using a filter that accurately mimics the spatial filtering effected by the skin to further equate the peripheral images in the two modalities. We found that vision consistently outperformed touch regardless of the precise perceptual task and of how familiar the patterns were. Based on an examination of both the earlier and present data, we conclude that visual processing of both familiar and unfamiliar two-dimensional patterns is superior to its tactile counterpart except under very restricted conditions.